This invention relates to improvements that greatly extend the wear life and increase the load strength of pintle-type industrial conveyor chains, and more particularly that achieve these ends without restricting the adaptability or versatility of chain form to various uses, adding to exterior bulk or objectionably increasing initial chain cost. The invention is herein illustratively described by reference to the presently preferred form thereof embodied in otherwise conventional C-type and H-type industrial conveyor chains; however it will be recognized that various changes and modifications therein may be made without departing from the essential features involved.
Pin wear and pin breakage susceptability of conventional chains of the types generally used in industrial conveyor operations are serious problems. Not only do they present an economic problem in terms of chain cost initially and in making repairs, but there is a greater cost and disaccommodation experienced in many used due to downtime of a plant when a critical process conveyor breaks unexpectedly under load. Frequent inspections are necessary to determine chain pintle condition, the pintles or pins usually being the critical part that breaks after wear and/or crystallization due to repeated flexure stresses under load. Visual inspections are at best difficult and unreliable, however, unless the conveyor is dismantled and the parts separately examined and/or tested. In most plants a procedure as elaborate and time consuming as this is not feasible, so the all too-common practice is to operate a conveyor line until it breaks or until a weekend, holiday or other convenient shutdown time when careful inspections and repairs or replacements can be made.
A further object of this invention is to provide wear extending, strengthening coupling means between links of such chains that can be more easily inspected visibly without fully disassembling the chain, that can be more easily repaired by weld-on deposits of metal in worn places when need by, and that can be expected generally to multiply the trouble-free, full-strength working life of such chains severalfold.
Another object hereof is to provide such link coupling improvements in such chains that also strengthen the chain links in another respect, normally through inherent exertion of selfcompacting forces when under load that eliminate spreading and breaking tendencies that end chamferring type of wear can cause in conventional pintle-type chains after pins wear thin and a looseness develops that can permits spreading apart of opposed link bar ends until there is failure.
A further object hereof is to so modify the coupling means in such chains as to greatly increase the working areas of the interengaged bearing surfaces such that stresses are not concentrated and actual wear per unit area is greatly reduced, yet without significantly increasing the amount of material in the chain or its external bulk, or presenting limitations on the kinds, shapes and sizes of fittings and attachments that may be mounted on or carried by such chains, or on the driving and guiding mechanisms working with them.